Cownter
Miltank (F) @
Leftovers
Ability: Sap Sipper
EVs: 252 HP / 36 Def / 220 SpD
Careful Nature
- Milk Drink
- Body Slam/ Return
- Earthquake/ Toxic/ Stealth Rock/ Fire Punch
- Heal Bell / Curse
You only need the first two moves to counter Serperior, but you can rearrange the other moves freely, depending on your team and on the support you want to provide (you can either be a setupper packing Firepunch and Return, or a Healbeller with rocks; There are many options and it's around your experience that you should decide which one is the best -even Double-Edge and TWave can be considered)
But the sure thing is that you can come onto any grass Type, that relies on his grass-stabs alone to be effective, as for example Serperior, get the +1 and then start becoming useful (Cursing up, poisoning somebody, spreading paralyzes with a +1 Body Slam, healbelling the opponent)
And if Serperior Glares you or your mates, the cow has some nice Healbell, a true mammal got the attributes.
The EVs are studied to be even on both defenive sides -if for any reason somebody wants to actually use it
Defensive calcs:
252 SpA Life Orb Serperior Dragon Pulse vs. 252 HP / 220+ SpD Miltank: 78-92 (19.7 - 23.3%) -- possible 5HKO after Stealth Rock and Leftovers recovery
252 SpA Life Orb Serperior Hidden Power Fire vs. 252 HP / 220+ SpD Miltank: 56-66 (14.2 - 16.7%) -- possible 8HKO after Stealth Rock and Leftovers recovery
So you tank it all day, steal the milk from your own calf and drink it all by yourself, and sit there producing some nice compost.
Offensive calcs:
0 Atk Miltank Body Slam vs. 0 HP / 0 Def Serperior: 79-94 (27.1 - 32.3%) -- guaranteed 4HKO
Either Miltank weighs off the opponent with BodySlam, or toxic stalls, or curses up and..
+3 0 Atk Miltank Return vs. 0 HP / 0 Def Serperior: 237-280 (81.4 - 96.2%) -- 62.5% chance to OHKO after Stealth Rock
Well, in that case Mitank could even prove to be useful against the whole side of the opponent team aswell, since it's pretty bulky.